System Assembly Considerations: “Hands-on” Means Higher Costs

Box-Build_Large_IMG9205_500pxIn the 20-plus years OCM Manufacturing has been building low/mid-volume, high-mix assemblies, we have seen literally thousands of product designs – some very good, some sort-of good, some that need improvement and some…well to be honest, some designs are pretty bad.We’re all familiar with the call for more collaboration between engineering and manufacturing (called design for engineering (DFM). Yet, all too often, there remains a gap in the development process between the design and the final assembly of a product. Often, PCB-level design issues are discussed; but, other elements of a product build that require just as much attention.

(OCM Manufacturing publishes many useful DFM Tips to help eliminate this gap – read them here).

One of the most expensive, yet overlooked, aspects of assembly is the manual tasks involved in putting a whole product together. To control costs, it’s desirable to automate as many procedures in the assembly chain as possible. If automation for a specific part of the process is not an option, then a designer must try to minimize the amount of manual work required in getting to the “finished goods” stage.

One particular area where this can be applied is in the interconnection of the various parts of a system that make up a complete unit (e.g. separate PCBs, modules or functional areas such as I/O, interface & control). Unfortunately, we still see designs that call for multiple wires to be manually crimped or hand-soldered to connect modules or boards before integration into their enclosures.

Design Tips for “Hands Off” Assembly
Hand-soldering and crimping are both time consuming and can drive up the cost of production more than necessary, sometimes pricing the product right out of its market. Here are just a few ways a designer can eliminate or reduce the amount of “hands-on” activities required at final assembly:

  • Design in a connector that can accommodate the number of wires needed between modules.
  • Consider the use of ribbon cable or flexible circuit strip for interconnections with many wires.
  • Use surface-mount connectors wherever possible. This automates the placement of the connector.
  • Remember that the orientation of the connector should be to the outside of the PCB, so leave space in the enclosure for the cable harness and connector counterpart.
  • Consider the use of flexible circuitry if your design consists of multiple, small PCBs in a daisy-chain configuration (series or parallel).
  • Try to ensure all through-hole (PTH) components are on the same side of the PCB, allowing as many PTH parts to be put through the wave soldering process as possible and reducing the parts to be inserted and soldered during the final assembly/integration stage.

These recommendations can apply to most electronic products, with extra care given to high-frequency RF products, in which wire length (whether in cable, ribbon or flex format) can affect signal integrity.

Enclosures & Mechanical Design
Special attention should be paid to the available space in an enclosure. Once the PCB(s), connectors, switches, lights, power supply and other functional areas are laid out, there must be room to properly interconnect these elements. This calls for inventors to work closely with industrial designers and mechanical engineers who have a good understanding of the work required to integrate their designs.

It also calls for designers and engineers to work closely with the companies that will be manufacturing and assembling the finished products in order to co-ordinate assembly cost factors with design ideas and esthetics. This means leaving enough space for cables, ribbons, flex circuits and mechanical parts to be integrated within the box.

New products are always exciting to the people who invent and innovate. Everyone wants to see their “baby” develop, successfully launch and perform well in its intended market. Design for manufacturing is absolutely critical to ensuring that brilliant products make it to market successfully.

Practically Speaking
A product may be the best thing imagined from a technical standpoint and the most beautiful-looking item on the shelf but, if it can’t be made and sold at a price that the market will bear, it will sit on that shelf and never be put to its intended use in the hands of its target customers.

To give a product a real chance to compete, every aspect of the manufacturing and assembly process must be given full consideration with respect to automation versus manual labor.

With ever-increasing solutions available, designers should spend the time looking for off-the-shelf products that facilitate the assembly of their systems and sub-systems and consult with a qualified manufacturing who will work as a ‘partner’ in minimizing costs, in each area of production, during the development cycle.

Contract manufacturers such as OCM Manufacturing can help with these issues before a design is completed (or, worse, before a product is already in the field and the economics preclude further design revisions). Foresight and collaboration just might be the key to enabling the successful launch and long lifecycle of the next new, relevant product that will benefit the world in many ways.

At OCM Manufacturing, we can work with designers to ensure that their plans and prototypes are manufacturable and therefore marketable. Contact one of our Program Managers for details about how we can help.